One thing to keep in mind, if you take somebody else's fish and they complain to DFO, I think you'd have a pretty tough time explaining why you're going around the ocean just randomly netting fish.
I believe you are only allowed to net fish which you have sport caught using a rod and reel.
Netting it (to be helpful) you could probably explain, but I think possessing it would be another story altogether.
These maniacs who never change course or speed (how many of them have tried to t-bone me right in my Port side I can't even count ) annoy me as much as everybody else, but I don't see how taking someone elses fish is sportsmanlike.